package basicJava.generics.generics1;

public class LinkedStack<T> {
	private static class Node<U>{
		U item;
		Node<U> next;
		Node(){
			item = null;
			next = null;
		}
		Node(U item,Node<U> next){
			this.item = item;
			this.next = next;
		}
		
		boolean end(){
			return item ==null&&next==null;
		}
	}
	
	private Node<T> top = new Node<T>();  //末端哨兵
	
	public void push(T item){
		top = new Node<T>(item, top);
	}
	
	public T pop(){
		T result = top.item;
		if (!top.end()) {
			top = top.next;
		}
		return result;
	}
	
	public static void main(String[] args){
		LinkedStack<String> lss = new LinkedStack<String>();
		for (String s:"Phasers on stun!".split(" ")) {
			lss.push(s);
		}
		String s;
		while((s=lss.pop())!=null){
			System.out.println(s);
		}
	}
}
